Image capturing apparatus, method for capturing an image shown in a display and arrangement of an image capturing unit and of a display as well as use of the image capturing apparatus and use of the arrangement

ABSTRACT

An image capturing apparatus having an image capturing unit and an image filtering surface in which the optical axis of the image capturing unit is disposed at an angle α to a normal of the image fitting surface.

The invention relates on the one hand to an image capturing apparatuswith an image capturing unit and an image fitting surface. On the otherhand, the invention relates to a method of capturing an image shown on adisplay. The invention further relates to an arrangement of an imagecapturing unit and of a display. The invention moreover relates to aplurality of uses of the image capturing apparatus and of thearrangement.

It has become increasingly desirable to optically capture an image shownin a display, for example on a portable apparatus, using a camera. Thisapplies particularly to cases in which the image shown in the displaycontains a machine-readable optical code, for example a barcode or adata matrix.

In Japan for example a system is being utilized that allows a mobilephone user to buy drinks at a drink vending machine without cash. Themobile phone user hereby dials a number written on the drink vendingmachine, the mobile phone user being then sent an optical code that isshown on the display of the mobile phone. The mobile phone user holdsthe display of his mobile phone in front of a receiving arrangementlocated within the drink vending machine. The receiving arrangementhereby registers the optical code which may next be decoded. If theoptical code is valid, the user is delivered the desired drink and theamount to be paid is debited with the phone bill.

Beside this concrete example, there exists a plurality of other imagecapturing arrangements serving to register an optical code. The majorityof these image capturing arrangements operate satisfactorily as long asthe optical code, as a marking, is firmly connected with a physicalsurface. Examples of such codes are printed codes or codes that havebeen burned into a surface by a laser. The apparatus operatesatisfactorily as long as the physical surface is not reflective and/oras long as the physical surface has not been covered with one or aplurality of transparent protecting layers.

The majority of these arrangements however fail to operate properly whenthe image is captured from markings applied to specular reflectingsurfaces, from markings disposed behind a glass pane and when the imageis captured from markings shown in an electronic display. The majorityof these arrangements more particularly fail to operate when they are toread from a liquid crystal display (LCD). This is due on the one side tothe fact that the majority of the displays for showing an image areoptimized for a human user and on the other side to the fact that thephysical surface of the display reflects incident light or that aprotecting layer disposed in front of a display reflects incident light,this light reflection negatively affecting the image capturing process.

In order however to achieve a required minimum contrast and a requiredminimum sharpness when capturing an image for correct optical coderegistration, a lighting condition is needed in most of the applicationcases in which the light is frontally incident on the display. Thetransparent layers disposed on or in front of the display alreadymentioned herein above in particular cause reflections that are alsodirectly incident on the image capturing unit, thus being superimposedupon the actual image to be captured by the image capturing unit.

Such type layers are for example the top cover layer of the actual LCD,a possibly existing touchscreen foil—often utilized for pocket PCs,PDAs, smart phones and communicators—and if applicable an upperprotective glass for protecting the LCD from mechanical stresses. Morespecifically, the upper protective glass is particularly problematic interms of a good image capture of an image shown in a display because itis made in most cases from a simple plastic material of a poor opticalquality on the one side and is on the other side often configured to bevery thick so as to be capable of performing its protective functionparticularly well. Moreover, the top protective glass is often curved sothat the light rays that are incident on the curved protective glass arereflected to many sides.

Generally, the reflections of lighting can only be reduced or avoidedwith difficulty. In order however to reduce the negative influences ofthese reflections onto a captured image, known image capturingarrangements are often provided with a very uniform diffuse lightingenvironment. Ideally, this lighting eliminates almost all of theartefacts in the image caused by lighting. This only provides a uniformgeneral brightening to the image and, as a result thereof, diminishesimage contrast.

Accordingly, prior art arrangements for capturing images from an LCDconsist of a camera the optical axis of which coincides with the normalof the display and of a coaxial lighting device that provideshomogeneous diffuse light to the display from the front. Moreover,physical light sources used for this purpose are not allowed to belocated in the light path of the image capturing camera in order forthem not to partially cover the image. It also makes little sense todispose the light sources behind the camera since the camera would thenbe disposed between the light source and the display and the display atleast partially be masked by the camera. With regard to the known imagecapturing arrangements, a virtual light source realized by means of asemi-transmitting mirror is being used in the light path as the lightingdevice.

Similar image capturing arrangements are also utilized to capture animage from a specular reflecting surface or if the area to be capturedis covered by one or several transparent layers so that the specularreflecting surface and/or the interface of the translucent layers actlike a mirror. As a result, the image capturing unit “sees” mirrorimages of the surrounding image capturing arrangement that aresuperimposed upon the image to be captured. In order to reduce thesedisadvantages, it is preferred to use a coaxial lighting device emittinga homogeneous diffuse light. A major disadvantage of this arrangementresides in the high cost of lighting devices of such a complexconstruction. Another disadvantage of the known arrangements moreoverresides in a non-ideal homogeneity of the illumination that is directlyreflected in the LCD, the protective glass or another surface capable ofreflecting light. Another disadvantage is that frontal illuminationalmost always involves reduced contrast, which on the one side restrictsthe achievable image quality and on the other side makes it considerablymore difficult to automatically register correctly an optical code inthe image.

Furthermore, what are termed diffusers are to be utilized in order toachieve the required homogeneity so that a great part of the generatedlight energy is absorbed and accordingly converted to heat. Conventionallighting devices accordingly exhibit a poor efficiency because a largeamount of electrical energy is needed which is for its major partconverted to heat.

It is the object of the invention to provide an apparatus and anarrangement respectively that largely avoid the disadvantages ofconventional image capturing arrangements.

The object of the invention is solved by an image capturing apparatushaving an image capturing unit and an image fitting surface in which theoptical axis of the image capturing unit is disposed at an angle α to anormal of the image fitting surface.

With the image capturing apparatus of the invention, a particularly lowcost possibility is provided on the one side to capture from a specularreflecting surface and/or from areas that are covered by transparentlayers images that exhibit high quality contrast and sharpness. It isthereby particularly advantageous that, on the other side, a highquality image can be captured from a display, more specifically from anLC-display.

This is particularly advantageous because the number of portableelectronic apparatus equipped with a display is constantly increasing onthe one side and because on the other side an ever increasing number ofportable electronic apparatus having such type displays is beinginvented by means of which the data are presented to the user in avisual form. This applies in particular to mobile telecommunicationapparatus and to electronic pocket computers. For example, higherresolution graphics-capable displays—with in parts several ten thousandpixel—have established themselves over line-oriented alphanumericaldisplays in mobile phones. The display technology utilized in most ofthe apparatus still is the liquid crystal—LC technology, which hassubstantially developed in the last thirty years. Moreover, pocketpersonal computers and PDAs for example have always been provided withgraphics displays. Meanwhile, add-on modules for pocket personalcomputers and PDAs exist which permit, in addition to their initialpurpose of utilization, the use of these apparatus as a mobile phone.Hybrid forms of pocket personal computers, PDAs and mobile phones alsoexist in the meantime. These hybrid forms are often called smart phonesor communicators. Hereto before, such type liquid crystal displays arealso used in pocket personal computers, PDAs, smart phones andcommunicators.

The term “image capturing unit” is to be construed herein as any devicethat is suited for digitally capturing an image. It is generally meantto include devices comprising a digital image capturing sensor. Such animage capturing unit may furthermore also comprise an optical devicesuch as a lens and an objective for example. The optical device therebysubstantially serves to project onto the image capturing sensor an imageof the scene “viewed” by the image capturing unit.

The term “image fitting surface” is to be construed as a transparentdevice against which an image to be captured is fitted or at least infront of which said image is positioned, said image being preferablyreproduced on a display or on a specular reflecting surface. In most ofthe application cases, the image fitting surface concurrently serves asa positioning aid for readily and accurately positioning the image to becaptured relative to the image capturing unit. There is no concern as towhether the image to be captured is brought near the image capturingapparatus or whether the image capturing apparatus is brought near theimage to be captured.

The image fitting surface is preferably configured to be planar and tobe a constituent part of the housing of an image capturing apparatus. Itis advantageously made from a glare-reducing material such as forexample an anti-reflection glass. In addition to a preferred“physically” present image, embodiment examples may exist in which theimage fitting surface is formed directly by a positioning aid. Thepositioning aid for example comprises a frame onto which a display ispositioned opposite the image capturing unit. The frame therebysurrounds a “virtual” area representing an image fitting surface inaccordance with the invention.

The term “optical axis” describes herein the main viewing direction ofthe image capturing unit. The main viewing direction thereby generallycoincides with an axis of symmetry of the optical device, such as a lensor an objective, of the image capturing unit. In accordance with theinvention the optical axis constitutes a viewing direction of the imagecapturing unit and is subject to the laws of ray optics. In this contextit is understood that the optical axis of the image capturing unit maybe broken or deviated by optical elements such as lenses, prisms ormirrors.

In accordance with the invention, the optical axis is further inclinedat an angle α to the normal of the image fitting surface and passes inthe simplest case between the image capturing unit and the image fittingsurface. If however the optical axis of the image capturing unit isdeviated by an optical device and the central light path is onlyincident upon the image fitting surface as a result of this deviation,the optical axis of the image capturing unit is also inclined at anangle α to the normal of the image fitting surface in the region betweenthe optical device and the image fitting surface.

The term “normal” refers to an imaginary line that is perpendicular tothe image fitting surface. In accordance with the invention, the normalpreferably passes through a point in which the optical axis is incidentupon the image fitting surface or upon a display brought in front of theimage capturing unit.

The term “display” is meant to include, in addition to a plurality ofdeveloped implementations of LCDs such as supertwisted nematic (STN),fast supertwisted nematic (FSTN), thin film diode (TFD), thin filmtransistor (TFT), low-temperature poly-silicone (LTPS), other displaytechnologies that do not make use of liquid crystals but for example ofelectroluminescent materials. Nearly all of the actual, and probably allof the future displays comprise a transparent “protective glass” thatcovers the imaging display area and protects the delicate parts of thedisplay from mechanical stresses and from dirt. Such type protectiveglass is often made from a transparent plastic material and not so oftenfrom a mineral glass. Also, almost all of the displays share the primarypurpose to create an image that is readily visible to a user when vieweddirectly.

In accordance with the present invention, the term “display” is not onlymeant to include a digital data display but also specular reflectinginformation-carrying surfaces. Generally, the term “display” includesany surface of an object that carries readable information in accordancewith the invention. There is no concern as to whether these surfaces areadditionally covered by one or a plurality of transparent protectivelayers. It is understood that far less complicated information receivingareas are included in the term display so that it is possible to captureimages from almost any information-containing area in accordance withthe invention.

Due to the fact that the normal is disposed at an angle α to the opticalaxis of the image capturing unit, the image capturing unit is disposedopposite the image fitting surface and, as a result thereof opposite adisplay, in such a manner that light rays incident upon the imagefitting surface or upon the display are not, or to a negligible extentonly, sensed or “seen” by the image capturing unit in the event of areflection. Accordingly, reflections originating from the image fittingsurface or from a display have no negative effects onto the imagecaptured. Accordingly, the image capturing apparatus of the inventionpermits to capture images of a higher quality than with the conventionalimage capturing arrangements in which the normal and the optical axisare oriented parallel to each other.

Furthermore, the image capturing apparatus of the invention permits tocapture sharper images with improved contrast, more specifically imagesfrom the displays of portable apparatus, preferably from LCDs, even ifthe LCD strongly reflects incident light or if the LCD is covered by oneor a plurality of transparent specular reflecting layers that stronglyreflect the incident light.

Under such adverse conditions, the image capturing apparatus of theinvention provides substantial advantages over known image capturingarrangements in terms of readability of optical codes from a display.

The term “optical code”—also referred to as “2D code” hereinafter—includes, with regard to the present invention, anyinformation-carrying marking the information of which is readable bymachine-visible means such as a digital capturing sensor. Such a code ismeant to be what is termed a “character” marking which is also known bythe name of “OCR”.

Moreover, by arranging an angle α between the optical axis of the imagecapturing unit and the normal of the image fitting surface, it ispossible to use a lighting device manufactured at low cost. This is madepossible by arranging the lighting device within the image capturingapparatus in such a manner that the actually unavoidable reflections ofthe lighting device upon the display and/or upon a protective glass arelocated outside of the lens coverage area of the image capturing unit.

It is known that displays relying on an LCD-technology in particularpossess an angle-dependent characteristic with regard to theirreadability. Substantial parameters such as contrast and sharpnessstrongly depend on the viewing angle of the LCDs. This particularlyapplies to reflective LCDs without background lighting which are mainlyutilized in portable apparatus. Nearly any LCD has an optimal viewingangle at which high contrast, good sharpness and additionally, in thecase of color displays, good color fidelity are obtained. This howevermeans that, if the actual viewing angle differs too much from theoptimum viewing angle, the display is no longer readable, or only withgreat difficulty. The tolerable difference from the optimum viewingangle is very little with portable apparatus in particular and is inmost cases no more than plus/minus some 10°. In conventional use of aportable apparatus, this is no disadvantage because the user holds theapparatus in his hand and intuitively adjusts the appropriate viewingangle. To allow convenient operation of such a portable apparatus, theLCDs of portable apparatus are generally constructed such that theoptimum viewing direction does not extend along the normal of thedisplay but is in most cases inclined at an angle of about 15° to 20° tothe normal.

It is therefore advantageous if the angle α between the optical axis ofthe image capturing unit and the normal of the image fitting surface ismore than 2°, preferably more than 5°.

In order to achieve a captured image of the best possible quality, it isadvantageous if the angle α is less than 50° or less than 35°,preferably less than 30°.

An objective is to achieve the least possible loss of contrast andsharpness in the largest possible region of the image fitting surface.It is therefore advantageous if the image capturing unit has an angle ofsight β of less than 30°, preferably of less than 15°. As a result, thelargest possible number of optical rays is oriented in the direction ofthe optical axis, departing therefrom only a little with accordinglylittle loss of contrast and sharpness. This is due to the fact that animage is only captured in the center of a lens coverage area of an imagecapturing unit i.e., substantially in a region along the optical axis,exactly at the angle α so that the image capture is well performed. Onthe borders of the lens coverage area however, the effective capturingdirection departs by about half the angle of sight from the optical axisof the image capturing unit. The angle of sight β is substantiallydetermined by the focal length of the image capturing unit. Using a longfocal length results in a small angle of sight β; using a short focallength, the angle of sight β is large. Accordingly, in order to avoidthe detrimental effects of a large angle of sight β, it is advantageousto use a long focal length. The focal length of the image capturing unitis to be considered long in accordance with the invention if it is atleast as long as double the length of the sensor of the image capturingunit. Accordingly, it is advantageous if the image capturing unit has afocal length that is more than double, preferably more than four times,the size of the maximum diagonal of an image capturing sensor of theimage capturing unit.

Particularly good image capture quality is achieved if the angle α is atleast half the size of the angle of sight β of the image capturing unit,preferably if it is at least as large as the angle of sight β of theimage capturing unit. The focal length is hereby advantageously chosenso as to prevent reflection of the image capturing unit on the imagefitting surface, which would result in a considerably reduced quality ofthe image captured.

In order to allow compact construction of the image capturing apparatusalso with a focal length chosen to be very long, it is advantageous todispose between the image capturing unit and the image fitting surfacean optical device by means of which the light paths between the imagecapturing unit and the image fitting surface can be advantageouslyredirected.

Advantageously, the optical device is hereby a mirror by means of whichthe light paths between the image fitting surface and the imagecapturing unit can be very easily redirected in terms of construction.

It has been found out that it is advantageous to provide controlledlighting to a display to be read, more specifically if said display isreflective, or to a specular reflecting surface that is to be read, inorder to thus achieve improved capturing results. It is thereforeadvantageous if the image capturing apparatus comprises a lightingdevice. It is understood that by redirecting the light paths the opticalaxis is redirected as well so that the angle α is meant to refer to theangle at which the possibly redirected optical axis is formed to thenormal of the image fitting surface on the site of the image fittingsurface.

In this context it is advantageous if the lighting device compriseslight-emitting diodes since light-emitting diodes are manufacturable ata low cost, are of a small construction, operate at a low voltage,generate but little waste heat and have a very long life span.

It is further advantageous if the light emitted by the lighting devicetravels substantially along the light path of the image capturing unit.By thus arranging the light-emitting means, the emitted light beams areincident upon the image fitting surface or upon a display to be read atabout the same angle at which the light path of the image capturing unitis inclined and at which the display is “seen” by the image capturingunit. As a result thereof, as compared to light which would otherwise beincident at another angle, the contrast and sharpness of the imagecaptured is less reduced.

More specifically, by arranging the optical axis relative to a normal ofthe image fitting surface and by selecting an image capturing unit witha long focal length, one achieves that neither the image capturing unitnor the lighting means of the lighting device are reflected by a surfaceto be read. For this reason, an expensive homogeneous coaxial lightingdevice providing light to the display by a virtual light source can beexcluded. Accordingly, the image capturing apparatus is an economicallyvery interesting alternative to conventional image capturingarrangements.

In another implementation variant the lighting device comprises coloredlight-emitting means, preferably colored light-emitting diodes.

In order to prevent ambient light or stray light from being incidentupon the image fitting surface and from being reflected in part or inwhole by said image fitting surface into the image capturing unit, it isadvantageous if the image capturing apparatus comprises an opticalscreen that is disposed outside of the light path of the image capturingapparatus. In order for the optical screen to optimally serve itspurpose, it is advantageous to have the optical screen disposed betweenthe image fitting surface and the image capturing unit and/or a lightingdevice.

It is particularly advantageous if the optical screen comprises alight-absorbing surface and if the light-absorbing surface is preferablyturned toward the image fitting surface. The light-absorbing surface isthereby preferably black. Such a light-absorbing surface is advantageousbecause it is reflected in the image fitting surface or in the displayor in the protective glass of a display and because the mirror image issuperimposed on the image actually to be captured by the image capturingunit. The light-absorbing surface hereby however merely generates ablack mirror image which, by being superimposed on the image fittingsurface, has no detrimental effect on the quality of the image captured.

It is further advantageous if the image capturing apparatus comprises ahousing portions of which preferably comprise a translucent material.The primary advantage of such a housing is that it protects thecomponent parts and devices mentioned herein above from externalphysical, more specifically mechanical, optical and/or electrical,influences. A particular advantage is achieved if parts of the housingare made from a light-impervious material and other parts of the housingfrom a translucent material. It is particularly advantageous toconfigure the part of the housing located in the light path of theoptical arrangement, for example the image fitting surface, as a windowmade from a reflection-reducing material. As a result, reflections onthe interfaces of the window or of the image fitting surface will notimpair the quality of the captured image.

It is further advantageous if the image capturing apparatus comprises apositioning device. The use of the apparatus according to its purpose ofutilization is facilitated if the side of the housing that lies in thelight path of the optical arrangement is equipped with a positioningdevice or is configured to be a positioning aid. At its simplest, thepositioning device consists of a planar surface that is held in front ofthe display or against which the display is pressed. As a result, it isadvantageous to configure the image fitting surface as a positioningdevice or at least to mount such a positioning device in proximity tothe image fitting surface.

It is particularly advantageous if the positioning device includes ameans for protecting a display or an apparatus containing said display.A padding made from a resilient material disposed around the imagefitting surface for example serves to prevent the apparatus helddirectly in front of the window or of the fitting surface from beingdamaged. Another advantage is that such a padding permits to avoid thatextraneous light is laterally incident on a display when the userslightly presses the display of the apparatus against the padding of thepositioning device.

Accordingly, it is advantageous if the positioning device comprises apadding that protects from damage an object brought to the positioningdevice and that further, in cooperation with the object, shields fromambient light the image capturing unit.

A display pressed against the positioning device or a specularreflecting surface pressed against the positioning device is thusadvantageously shielded from ambient light.

The object of the invention is also solved by a method for capturing animage shown in a display by which an image capturing unit is heldobliquely relative to the display during the image capturing process. Byholding the image capturing device “obliquely” relative to the display,the display is held at an angle to an image capturing unit thatcorresponds, or at least comes very close, to the optimum viewing angleof an LC display for example. As a result, the image capture quality ofthe image shown in the display is substantially improved overconventional image capturing methods.

In the present context, the term “display” also includes, as alreadyexplained herein above, specular reflecting surfaces. In connection withsuch type surfaces, it is advantageous if the beams that are reflectedfrom the display and lie in the light path of the image capturing unitare absorbed by an optical screen.

The method of the invention permits to use much simpler lighting devicesfor illuminating a display than hereto before so that the method issubstantially simplified over known image capturing methods.

In order to make the method less sensitive to stray light, it isadvantageous to substantially place the display on an image fittingsurface or vice versa. This permits on the one side to largely preventambient light from being incident on the display so that the ambientlight does not reach the display or only with difficulty and is notreflected from the display. This prevents image capture of the imagecapturing unit from being possibly disturbed. On the other side, goodpositioning of the image to be captured relative to the image capturingunit or vice versa is achieved.

Particularly good image capture results are obtained if during the imagecapturing process the display is illuminated by light having awavelength of between 450 nm, preferably between 500 nm, and 600 nm,preferably 550 nm.

It has hereby been found out that it is advantageous if the display isilluminated by light beams that are substantially oriented along thelight path of the image capturing unit. By thus illuminating the displayalong the light path of the image capturing unit, the light is caused tobe incident on the display at substantially the same angle at which thedisplay is “seen” by the image capturing unit. This offers the advantagethat contrast and sharpness of the captured image are not reduced asthis is the case when the display is illuminated at another angle.

If, in a method variant, a “physical” image fitting surface is notprovided, the optical axis forcibly extends between a display and animage capturing unit or an optical device.

The invention is further solved by an arrangement consisting of an imagecapturing unit and a display in which the optical axis of the imagecapturing unit is disposed at an angle α to a normal of the display. Theadvantages of such an arrangement have already been discussed inconnection with the image capturing apparatus of the invention. Thedifference compared to the image capturing apparatus is that thearrangement of the invention can dispense with a housing. A low costalternative is thus obtained. Due to the open build of the arrangementof the invention, it is however advantageous to limit its use toautomated stationary operation. For example, displays or other specularreflecting surfaces are automatedly brought to the image capturing unitof the arrangement of the invention. Or, the arrangement is mounted intoan already existing device.

Moreover, the use of the image capturing apparatus described and the useof the arrangement for capturing an image from a display, morespecifically from an LC-display or from a specular reflecting surface,is advantageous.

More specifically, the use of the image capturing apparatus and the useof the arrangement described are particularly advantageous to capture animage from a surface that is covered by at least one transparent layer.

The use of the image capturing apparatus and the use of the arrangementdescribed is advantageous for reading an optical code that is preferablydisplayed on a display or on a specular reflecting surface.

For example, in the field of drink packages, the surfaces are normallybright, meaning specular reflecting. Further examples of specularreflecting surfaces are PET bottles, glass bottles, drink cans made fromtin and drink boxes as well as humidity-resistant labels.

The invention described herein is particularly suited for readingmarkings on cans and bottles. The introduction of a deposit system fordisposable packages requires the packages for which a deposit has to bepaid to be provided with a marking so that the packages for which adeposit was paid—deposit paid—may be distinguished from those for whichno deposit was paid—no deposit paid—.

It is advantageous if this marking includes additional information suchas e.g., information on the deposit amount, the material, themanufacturer and/or the bottler because this additional informationfacilitates or even actually makes it possible to balance the cashflow—deposit clearing. Such a balance is more specifically necessary ifthe package is returned at a different place from where it has beenbought. It may even be advantageous to provide each package on whichthere is a deposit with a clear identification code and to keep theinformation on the various packages in a data bank.

Another advantage is achieved if the deposit marking is scannable orreadable by an automated process. A marking that would be scanned orread by humans only and not by machines would impair or hinder theautomation-assisted return of the packages and would add tremendouslogistical expense to the deposit clearing process.

It is therefore advantageous if the deposit marking includes an opticalcode, for example a data matrix code that is readable by a reader. Theinvention is advantageously suited for reading such type deposit marks,more specifically also with regard to cylindrical bright or round brightsurfaces.

Another application is in the field of mobile tickets or of an accesscontrol to a closed area. Tickets for major events such as concerts,sport events may be ordered by mail, more specifically on the internet.The advantages associated therewith are well-known. Hereto before,tickets thus ordered have been delivered by mail in the form of materialtickets so that a number of days must separate the selling of thetickets from the actual event. An electronic ticket in the form of anoptical code may be used instead of a material ticket, said optical codebeing adapted to be displayed on a current mobile phone display. Such anelectronic ticket can be sent via wireless transmission without loss oftime. This makes it possible to buy tickets for example from home,shortly before the beginning of the event, which is otherwise onlypossible at the box office.

Moreover, code readers of the invention may be used for reading forexample a 2D-code at event entrance. The scanned code is verified tocheck whether the code represents a valid ticket. Upon successfulverification, access to the event is granted. It may hereby beadvantageous if the code reader comprises signalling means such as anacoustic sound signal, an optical display or an electrical wirebound orwireless output signalling the validity of the ticket. Signalling via anelectrical wirebound or wireless output is particularly advantageous ifthe access system comprises a corresponding electrical wirebound orwireless input. The code reader may then notify the access system thatthe ticket is valid upon which the access system opens an automatic doorfor example.

It is also possible to use code readers at another location than at theevent entrance. In this context, it is advantageous if the code readercomprises a printer or is connected to a printer. With such a codereader it would be possible to exchange the electronic ticket displayedon the mobile phone display for a printed ticket. Then, access could begranted at the event entrance upon presentation of the printed ticket.

In this case it is not the 2D code that acts as the actual ticket butits content. It is therefore of no concern whether a 2D code is sent ina graphics format e.g., MMS or whether the code content only is sent andis converted into a 2D code by a program running in the mobile phoneprior to being displayed on the display.

It would also be possible to transport the code content in anothermanner than by representing it on the display and to transport an imagecapture through the reader to the access system e.g., using an infraredinterface or via SMS. Passing through the phone display however isadvantageous because this way results in the least expense to the phoneuser.

Further applications are in the field of digital coupons on a mobilephone. The majority of mobile phone users only accept advertisingmessages on their mobile phone if they offer direct advantages to theuser. In order to win this range of users for these advertisingmessages, it is necessary to grant the users of the advertising serviceadvantages they would not have if they did not use the service.

For this purpose, it seems appropriate to send to the users toleratingadvertising messages on their mobile phone, together with saidadvertising messages, electronic coupons that can be redeemed within acertain period of time in determined shops such as cinemas, theatres,and so on. A coupon may for example grant special discounts, promiseextras or small presents.

The advantage of this type of advertising is the improved efficiency. Onthe one side, the required declaration of consent of the user impliesthat the advertisement will match the target group. On the other side,future localisation services permit to adapt the sending of advertisingmessages to the whereabouts of the user.

The difficulty of redeeming electronic coupons stored in the mobilephone for example, meaning to “retrieve” them from the mobile phone, issolved by using a 2D code as a coupon and by using a reader of theinvention at the site of redemption. It is for example possible to equipeach counter of a participating department store with a reader. It isthereby advantageous if the reader is connected to the counter throughconnection means. This applies in particular to discount coupons. Such aconnection permits to readily transmit the coupon to the counter system,thus avoiding subsequent manual booking of the coupons.

Precisely in the introductory phase however it is also possible to onlyinstall one reader or but a few readers on central locations in thedepartment store. Together with a printer, said reader is integratedinto a readily operable apparatus. The user holds the mobile phone withthe 2D code in front of the reader and receives in return a “physical”coupon he may then redeem at a counter. It is thereby advantageous ifthe physical coupon comprises a barcode that may be read by the counterand be processed by the counter system. The particular advantage of thisway of proceeding is that the counter sales personnel is capable ofprocessing these physical coupons in much the same way as conventionalcoupons that are for example printed in newspaper supplements. Ideally,the counter sales personnel needs not receive complicated extratraining.

Once the 2D code has been read and used in the system, for example forprinting a “physical” coupon, the 2D code or the information of the 2Dcode is deactivated so that the code can only be used once. If however,the code is to be used several times, it may remain active for anappropriately longer period of time.

Further objects, advantages and features of the present invention willbecome more apparent upon reading the description of the attacheddrawing that illustrates, by way of example, the arrangement of theinvention and the image capturing apparatus of the invention.

For the purposes of clarity, like elements or components will bear thesame reference numerals.

In the drawing

FIG. 1 is a schematic view of an image capturing arrangement of theinvention,

FIGS. 2 and 3 each are a schematic view of an image capturingarrangement with an optical screen,

FIG. 4 is a perspective view of a code reader,

FIGS. 5 and 6 each are a perspective view of a code reader incooperation with a mobile phone,

FIG. 7 is a schematic side view of the code reader of the FIGS. 4 to 6with an image capturing arrangement of the invention,

FIG. 8 is a schematic view of another code reader with a control panel,a display and a keyboard and

FIG. 9 is an exemplary embodiment of a coupon that has been issued bymeans of the code reader of FIG. 8.

The exemplary embodiment shown in FIG. 1 includes an image capturingunit 1 that is disposed opposite a display 2 of a pocket personalcomputer 3. The image capturing unit 1 has a light path 4 with an angleof sight β. The image capturing unit 1 is thereby disposed opposite thedisplay 2 in such a manner that the light path 4 almost completelycovers the display 2 so that the image capturing unit 1 completely“sees” an image 5 shown by the display 2.

The image capturing unit 1 has an optical axis 6 that is inclined at anangle α to a normal 7.

The normal 7 is perpendicular to the display 2 and passes through apoint of intersection 8 in which the optical axis 6 meets the display 2.

If the display 2 is partially reflective or if the display 2 is coveredby partially reflective transparent layers 32 (see FIG. 7), the imagecaptured by the image capturing unit 1 is composed of the image of thedisplay 2 or of the image 5 shown in the display 2 and of an image ofthe reflections (not shown). In a conventional arrangement in which theoptical axis 6 of the image capturing unit 1 coincides with the normal7, the image capturing unit 1 is at least partially reflected in thedisplay 2 or in the layers superimposed on the display 2, so that theimage captured by the image capturing unit 1 contains the mirror imageof the image capturing unit 1.

In the arrangement 1 of the invention as shown in FIG. 1, the imagecapturing unit 1 does not “see” itself in the mirror image but “looks”past its own mirror image. Instead, the image capturing unit 1 “sees”the mirror image of a region 9 of the scene located to the side of theimage capturing unit 1. A particular advantage thereby is that a region9A, in which the image capturing unit 1 is disposed, is not used forcapturing the image.

Advantageously, further structural elements for controlling reflectingeffects may thus be provided in the region 9 (see for example the FIGS.2 and 3). It is more specifically advantageous to install an opticalscreen 12 (see FIGS. 2 and 3) made from a light-impervious material inthis freed region 9 which the image capturing unit 1 “sees” as a resultof reflections.

The arrangement 10 shown in FIG. 2 includes an image capturing unit 1for capturing an image from a specular reflecting surface 11. In thisexemplary embodiment as well, the image capturing unit 1 ischaracterized by an optical axis 6 and by a light path 4 with an angleof sight β, with the optical axis 6 intersecting the specular reflectingsurface 11 at the point of intersection 8. Taking its departure fromthis point of intersection 8, a normal 7 extends perpendicularly to thesurface 11 and is inclined at an angle α to the optical axis 6.

Furthermore, the arrangement 10 comprises an optical screen 12 that isprovided with a light-absorbing black surface 13. Reflections that mightreduce image capture quality are thus prevented. The light-absorbingsurface 13 appears “black” even when it is illuminated. Advantageously,no reflection that is visible to the image capturing unit 1 occurs as aresult thereof.

The arrangement 14 shown in FIG. 3 comprises an image capturing unit 1in front of a specular reflecting surface 11 with an optical screen 12.It is advantageous to keep zone 15, which is indicated here by hatchedlines, free from light sources since light sources disposed in this zone15 would cause deleterious reflections in the captured image. Moreover,the hatched zone 15 is also the only zone from which light beams arereflected onto the specular reflecting surface 11 and, as a resultthereof, into the image capturing unit 1.

The arrangement 14 of the invention described herein allows for a highdegree of freedom for constructing the same. More specifically,additional lighting devices 39 (see FIG. 7) may be mounted almostanywhere within the image capturing arrangement 14 without causingdisturbing reflections on the specular reflecting surface 11. Anotheradvantage is the considerably improved tolerance to externally incidentextraneous light.

The code reader 16 shown in the FIGS. 4 to 6 includes the functioningprinciple of the arrangements 10 and 14 of the invention described inthe FIGS. 1 to 3. The code reader 16 includes a housing 17 providingoutstanding protection against external influences.

The front side 18 of the code reader 16 is partially made from ananti-reflection glass window 19. The remaining part of side 18 at leastpartially includes a positioning aid 20. The code reader 16 furthercomprises mechanical fastening means 21 and 22 as well as electricalconnection means 23.

The mechanical fastening means 21 and 22, which are implemented here asan internal thread by way of example, permit to fasten it to otherobjects and to mount it into other apparatus such as vending machines oraccess control systems without any problem.

The electrical connection means 23 serve to supply the apparatus withelectrical energy and to electronically exchange data. It is morespecifically possible to send information from the code reader 16 to aperipheral unit (not shown herein) via the electrical connection means23. Such information may for example be the image captured by the imagecapturing unit 1 (see for example the FIGS. 1 to 3), the content of acode decoded by the code reader 16 or status messages of the code reader16. It is also possible to send information from the periphery to thecode reader 16. As a result, it is possible to parameterize and tomaintain the code reader 16 from the outside or to trigger optical andacoustical signalers 41 (see FIG. 7) contained in the code reader 16.

A mobile phone 24 (see FIGS. 5 and 6) can be disposed in front of thecode reader 16. The code reader 16 is hereby used to read an opticalcode 25 displayed on an LCD 26 of the mobile phone 24. The verticalmounting position of an arrangement 10, 14 indicated here isparticularly advantageous when the code reader 16 is used in outsideareas 27 because the ambient light there is bright and is mainlyradiated from the top downward. The vertical mounting position permitsto prevent disturbing direct sun light 28 from being radiated onto theimage capturing unit 1.

To read the code 25, the user holds the display 26 of the mobile phone24 under the code reader 16 and in front of the window 19 of the codereader 16. The user is assisted by the positioning device 20 so that, byplacing the mobile phone 24 against the positioning device 20, anadvantageous angle between the LCD 26 and the optical axis 6 of theimage capturing unit 1 is automatically obtained. During reading of thecode 25, the code content is transmitted via the electrical connectionmeans 23 to a superior system (not shown herein) that takes over thefurther processing of the code content.

In order to further facilitate positioning, the side 29 that is turnedtoward the user comprises another transparent zone 30. Through this zone30, the user sees the LCD 26 of the mobile phone 24. This substantiallyfacilitates positioning. Finally, positioning may be further assisted byacoustical and optical signalling that delivers a check-back signal tothe user as soon as the optical code 25 to be read has been read. Thissignalling may thereby occur either directly on or in the code reader 16or through a superior system (not shown herein) that communicates withthe code reader 16 via the connection means 23. In conventionalarrangements, another transparent zone 30 would have deleterious effectsonto the quality of the captured image because extraneous light beingexternally incident through this opening would be reflected from thedisplay 26 into the image capturing unit 1 (see FIGS. 1 to 3). In thepresent arrangement, by contrast, light being possibly externallyincident through the transparent zone 30 is reflected from the display26 onto the light-absorbing surface 13 of the optical screen 12 only(see FIGS. 2 and 3) where it is absorbed and thus rendered harmless toimage capture.

In the code reader 16, an image capturing unit 1 is spaced opposite animage fitting surface 31. The image capturing unit 1 receives the code25 of the LCD 26. The LCD 26 is hereby protected by a protective glass32 of the mobile phone 24.

Using a small angle of sight β for the image capturing unit 1 isadvantageous for capturing an image but results in a large build of thecode reader 16. In order to keep the build of the code reader 16 small,the light path 4 of the image capturing unit 1 is redirected by a mirror33. This makes it possible to arrange the image capturing unit 1together with other structural elements of the code reader 16. Forexample, an image processing unit 34 and a connection unit 35 as well asa signaller 41 are disposed in a free zone 36 behind the optical screen12.

Another advantage of redirecting the light path 4 by a mirror 33 is thatalmost all of the components may be mounted at right angles in arectangular housing 17, which considerably reduces construction expense.Only the mirror 33 and the optical screen 12 need oblique-angledfasteners 37 and 38. It is particularly advantageous if the mirror 33and the optical screen 12 are mounted during manufacturing of thehousing 17 already.

The image capturing arrangement 10, 14 (see FIGS. 2 and 3) within thecode reader 16 additionally comprises a lighting device 29 thatcomprises light-emitting diodes 14 for illuminating the LCD 26. Thelight-emitting diodes 40 are thereby disposed in immediate proximity tothe image capturing unit 1 and emit light substantially in the directionof the light path 4 of the image capturing unit 1.

The arrangement of the light-emitting diodes 40 in immediate proximityto the image capturing unit 1 introduces an effect of benefit in theimage capturing process. Due to the proximity to the image capturingunit 1 and to the light being emitted in the direction of the light path4 of the image capturing unit 1, the light reflected from the LCD 26 orfrom a protective glass cover 32 is directed onto the optical screen 12with the absorbing surface 13 so that it is prevented from causingdeleterious effects. With LCDs 26 in particular, another advantageachieved is the improved sharpness because parallax errors are avoidedthrough differing angles of sight and of lighting.

It may be advantageous to arrange the lighting device 39 in such amanner that the main illumination direction is slightly different fromthe direction of the optical axis 6 of the image capturing unit 1. Thisis due to the fact that not all the zones of the LCD 26 are spaced thesame distance from the light-emitting means 40 so that they areilluminated at different intensities. With the code reader 16 shown inthis exemplary embodiment, this effect is compensated by slightlytilting the lighting device 39 so as to obtain a uniformly illuminatedLCD. In this exemplary embodiment, the light-emitting diodes emit yellowand green light. This is advantageous because many LCDs 26 have thehighest contrast with a light of this color.

The code reader 16 moreover includes an acoustical signaller 41 thatsends a signal that the optical code 25 is being read. The signaller 41can be triggered directly by the code reader 16, meaning totally byitself, or via the electrical connection means 23.

The code reader 50 for reading an optical code 25 (see FIG. 6) shown inFIG. 8 comprises a housing 51 on which there are disposed a read window52, a positioning aid 53, an optical output unit 54, a control panel 55,a keyboard 56 and a voucher printer 57, for example for issuing a coupon58 (see FIG. 9). The code reader 50 further comprises various connectionmeans on its rear side 59. The code reader 50 is for example providedwith a connecting cable 60 through which the code reader is suppliedwith energy. The code reader 50 further comprises a connection terminal61 through which it can be connected to an Ethernet. The code reader 50further includes a Bluetooth interface 62 for establishing a wirelessconnection to a back office system (not shown herein). It is understoodthat such a wireless connection can be realized not only via a Bluetoothinterface 62 but also via a GPRS or a W-Lan interface (not shownherein). Accordingly, the connection means 61 can also be realized bymeans of an RS232 standard. It is more specifically possible toconfigure, to maintain the code reader 50 and/or to interrogatestatistical data from the back office system. In order to permit thereading of an optical code 25 (see FIG. 6) from a display 26 of a mobilephone 24, the LCD display 26 is held in front of the read window 52 ofthe code reader 50. In order to be capable of positioning a display 26or a surface of an object comprising an optical code to be read in frontof the read window 52 in a particularly easy manner, the read window 52is framed by the positioning aid 53. In this exemplary embodiment, thepositioning aid 53 is made from a relatively soft plastic material thatwill not damage the display 26 pressed against the positioning aid 53.Used in connection with the display 26 pressed against the read window52, the positioning aid 53 moreover serves as a protection againstambient light 63 so that the reading of the code 25 from the display 26is, as far as possible, not hindered by the additionally incidentambient light 63.

To the left of the read window 52 there are located the optical outputunit 54, the control panel 55 and the keyboard 56. User tips and statusmessages such as “please place the display of your mobile phone onto theread window”, “please enter your pin in on the keyboard”, “invalidticket”, “please wait, your coupon is being printed”, “coupon alreadyredeemed”, “no paper”, “out of order” can be displayed at the opticaloutput unit 54.

Authorization data, a pin for example, can be entered in on keyboard 56.The operating personnel can program the code reader 50 to a determinedapplication mode, using the keyboard 56. It is hereby advantageous ifthe operating personnel first have to get the authorization at the codereader 50. This may for example occur by entering a system PIN in on thekeyboard 56 or through an optical code via the read window 52. Forexample, the code reader 50 is configured by the operating personnelaccording to a menu by means of the keyboard 56 and the optical outputunit 54—in a way similar to that currently used with mobile phones.

With the voucher printer 57, a physical coupon 58 or another ticket isprinted. The coupon 58 is hereby issued from the code reader 50 throughan output slot 64 of the voucher printer 57.

The coupon 58 (see FIG. 9) issued in this exemplary embodimentcomprises, in addition to a description of how to use the coupon, abarcode 66. The barcode 66 may for example be scanned at a counter (notshown herein) together with a product to be purchased (nor shown herein)so that the counter system deduces the credit of the coupon 58 from theprice of the product.

It is understood that the code readers 16 and 50 described herein aboveas well as the arrangements described in connection with the inventionare only first exemplary embodiments of the present invention and arenot intended to limit the scope of the invention in any manner.

1. A method for using an image capturing apparatus in which a code froma mobile telephone device is read and the contents of the code aretransmitted to a superordinate system, wherein the code is decoded,wherein it is verified whether the code represents a valid electronicticket and furthermore characterized in that the code or the informationof the code is deactivated once the code has been read and used in thesystem and the electronic ticket on the mobile telephone display isexchanged for printed ticket by printing out a physical coupon or othertype of ticket is printed out by means of a coupon printer.
 2. Themethod as specified in claim 1, wherein the coupon has a barcode (66).3. The method as specified in claim 2, wherein the barcode (66) isscanned in at a counter together with a product to be purchased.
 4. Themethod as specified in claim 1, wherein the image capturing apparatus isconfigured or maintained by the back office system.
 5. The method asspecified in claim 1, wherein the code reading device (50) is programmedto a certain application mode by means of a keyboard (56).
 6. The methodas specified in claim 1, wherein operating personnel authorize a certainapplication mode on the code reading device prior to programming.
 7. Themethod as specified in claim 1, wherein an adjustment of advertisingmessages to the location of a user are undertaken by a localizationservice.